How to register guests for a free event and still build your email list
By Kelsey Gilbert-Kreiling | Co-founder, Eventually
The short answer: Use a short registration form with name and email, add a clear opt-in checkbox for your newsletter, and send the guests who check it to your email platform tagged with the event. The RSVP gives you a guest list. The opt-in turns the right guests into subscribers without adding anyone who didn't ask.
Why free events are your best list builders
A free open house, a community night, or a sample class asks very little of a new guest. The people who show up have already spent an evening with you. As subscribers, they're far warmer than anyone who clicked a pop-up.
But registering for an event isn't the same as signing up for your newsletter. Treating it that way costs you trust, and it can run against the email rules where your guests live.
What to avoid
Adding every registrant to your list. People who didn't opt in unsubscribe, ignore you, or mark you as spam, which hurts delivery for everyone else.
A pre-checked box. It inflates your list with people who never chose it.
A vague label. "Marketing emails" gets fewer yeses than a sentence that says what they'll actually get.
Separate forms for RSVP and newsletter. Two forms means most people fill out one.
How to set it up
1. Keep the form short
Name, email, and one question at most. Every extra field costs registrations on a free event.
2. Add an opt-in checkbox in your voice
Leave it unchecked and make the label specific: "Send me the monthly class calendar" or "Tell me about the next open studio."
3. Tag subscribers by event
In your email platform, tag everyone who opts in with the event they came from. A tag like "open-house-spring" lets you send a follow-up that references the night they attended.
4. Send the logistics separately
Confirmations and reminders go to every registrant, since they're about the event they signed up for. Newsletters go only to people who opted in.
5. Follow up with the next thing
A day or two after the event, send opted-in guests a short note: thanks for coming, here's what's next. That first email sets the tone for everything after it.
Your options on Squarespace
A Squarespace form block can take RSVPs and connect to your email tools, and a newsletter block can sit right beside it. That works for small, casual gatherings. It doesn't cap attendance, send a ticket, or give you a guest list to check in against, so it gets harder as free events grow.
How free events work in Eventually
Eventually is event ticketing for calendar-centric businesses, built as a Squarespace-first extension. Free events use a simple RSVP-style flow: guests register without going through the full Squarespace Commerce checkout, and they receive a confirmation right away. See Free events and the RSVP flow
To grow your list, connect Kit. You choose which event types send guests to Kit and tag subscribers, and registration includes an opt-in checkbox with a label you can edit to match your voice. Free events still get capacity, a guest list, and check-in. See Connect Kit.
If you use Klaviyo, Eventually can sync registrations to Klaviyo lists and triggers and send published events to your Klaviyo catalog. Keep newsletter sends limited to guests who opted in. See Connect Klaviyo.
What to do right now
If you add every RSVP to your list today: Stop, and add an opt-in checkbox to your next event.
If your opt-in rate is low: Rewrite the checkbox label to name exactly what they'll receive.
If you run free and paid events: Use the free ones to build the list, then invite that list to paid events first.
If you're unsure about email rules: Check the requirements for the countries your guests are in before importing anyone.
The bottom line
A free event is an introduction. The opt-in is the guest saying they'd like to hear from you again.
Ask clearly, keep your word about what you send, and the list you build will be people who actually want the next invitation.
Keep reading:
→ Event Ticketing for Nonprofits on Squarespace: Protect Your Revenue
→ How to move your events off Eventbrite without losing your list
See it in action:
→ Plans, including the free tier
Turn RSVPs into regulars
Free event registration that connects to Kit and Klaviyo, on your own Squarespace site. Get started at eventuallyticketing.com.